TY - JOUR
T1 - Investigation of the cerebral hemodynamic response function in single blood vessels by functional photoacoustic microscopy
AU - Liao, Lun De
AU - Lin, Chin Teng
AU - Shih, Yen Yu I.
AU - Lai, Hsin Yi
AU - Zhao, Wan Ting
AU - Duong, Timothy Q.
AU - Chang, Jyh Yeong
AU - Chen, You Yin
AU - Li, Meng Lin
N1 - Funding Information:
We acknowledge the National Science Council, R.O.C., for its support of this research (NSC Nos. 97-2221-E-007-084-MY3, NSC 100-2221-E-007-010-MY2, 96-2220-E-009-029, 97-2220-E-009-029, 99-2221-E-009-154, and 99-2911-I-009-101), as well as funding support from the National Tsing Hua University (Boost program 98N2531E1) and the Ministry of Education, Taiwan. The authors would also like to thank Po-Hsun Wang for his help in developing the fPAM system.
PY - 2012/6
Y1 - 2012/6
N2 - The specificity of the hemodynamic response function (HRF) is determined spatially by the vascular architecture and temporally by the evolution of hemodynamic changes. Here, we used functional photoacoustic microscopy (fPAM) to investigate single cerebral blood vessels of rats after left forepaw stimulation. In this system, we analyzed the spatiotemporal evolution of the HRFs of the total hemoglobin concentration (HbT), cerebral blood volume (CBV), and hemoglobin oxygen saturation (SO2). Changes in specific cerebral vessels corresponding to various electrical stimulation intensities and durations were bilaterally imaged with 36 × 65-μm2 spatial resolution. Stimulation intensities of 1, 2, 6, and 10 mA were applied for periods of 5 or 15 s. Our results show that the relative functional changes in HbT, CBV, and SO2 are highly dependent not only on the intensity of the stimulation, but also on its duration. Additionally, the duration of the stimulation has a strong influence on the spatiotemporal characteristics of the HRF as shorter stimuli elicit responses only in the local vasculature (smaller arterioles), whereas longer stimuli lead to greater vascular supply and drainage. This study suggests that the current fPAM system is reliable for studying relative cerebral hemodynamic changes, as well as for offering new insights into the dynamics of functional cerebral hemodynamic changes in small animals.
AB - The specificity of the hemodynamic response function (HRF) is determined spatially by the vascular architecture and temporally by the evolution of hemodynamic changes. Here, we used functional photoacoustic microscopy (fPAM) to investigate single cerebral blood vessels of rats after left forepaw stimulation. In this system, we analyzed the spatiotemporal evolution of the HRFs of the total hemoglobin concentration (HbT), cerebral blood volume (CBV), and hemoglobin oxygen saturation (SO2). Changes in specific cerebral vessels corresponding to various electrical stimulation intensities and durations were bilaterally imaged with 36 × 65-μm2 spatial resolution. Stimulation intensities of 1, 2, 6, and 10 mA were applied for periods of 5 or 15 s. Our results show that the relative functional changes in HbT, CBV, and SO2 are highly dependent not only on the intensity of the stimulation, but also on its duration. Additionally, the duration of the stimulation has a strong influence on the spatiotemporal characteristics of the HRF as shorter stimuli elicit responses only in the local vasculature (smaller arterioles), whereas longer stimuli lead to greater vascular supply and drainage. This study suggests that the current fPAM system is reliable for studying relative cerebral hemodynamic changes, as well as for offering new insights into the dynamics of functional cerebral hemodynamic changes in small animals.
KW - Electrical stimulation
KW - Functional photoacoustic microscopy
KW - Hemoglobin oxygen saturation
KW - Total hemoglobin concentration
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U2 - 10.1117/1.JBO.17.6.061210
DO - 10.1117/1.JBO.17.6.061210
M3 - Article
C2 - 22734740
AN - SCOPUS:84868648798
SN - 1083-3668
VL - 17
JO - Journal of Biomedical Optics
JF - Journal of Biomedical Optics
IS - 6
M1 - 061210
ER -